Conventional gas turbine engines require a substantial amount of external energy during start-up in order to achieve an operating speed where the engine will self-sustain and then be capable of providing output power. In some instances, particularly with smaller engines, the weight and volume of a starting system can approach that of the basic engine itself, particularly when cold conditions are present, or if a fast start-up time is required, and/or there are ancillary drags present. Furthermore, surging (reverse air flow) is a troublesome characteristic in a gas turbine engine that presents difficulties during starting as well as during continuous full load operation.
The present invention is directed to overcoming one or more of the above problems.